There are numerous designs of projectiles containing incendiary or explosive compositions. Such projectiles are conventionally configured such that the incendiary or explosive composition becomes ignited upon, or shortly after, the projectile's contact with an intended target. Ignition of the incendiary or explosive composition is intended to inflict additional damage on the target (i.e., beyond that which is caused by the physical impact of the projectile with the target). Such additional damage may result from the pressure of the explosion, the burning of the composition, or both. Depending on the configuration of the projectile, ignition of the incendiary or explosive composition may also be accompanied by fragmentation of the projectile casing thereby providing additional shrapnel-like components that spread out to create a larger area of impact and destruction.
Some exemplary projectiles containing an incendiary or explosive composition are described in U.S. Pat. No. 4,419,936 to Coates et al. The Coates patent generally discloses a ballistic projectile having one or more chambers containing a material that is explosive, hypergolic, incendiary or otherwise reactive or inert. The material may be a liquid, a semi-liquid, a slurry or of solid consistency. Initially, the material is hermetically sealed within a casing of the projectile but is released upon impact of the projectile with a target causing the projectile casing to become fragmented.
In many cases, projectiles containing an incendiary or explosive composition are designed to provide increased penetration of the projectile into a given target such as, for example, an armored vehicle. One such projectile is the MK211 armor piercing incendiary (API), a projectile that is configured for penetration of armor plating. However, the MK211 and similar projectiles have proven to be relatively ineffective against what may be termed thin-skinned targets. Thin-skinned targets may include, for example, liquid filled fuel tanks or other similar structures having a wall thickness of, for example, about 0.25 inch or less. Thin-skinned targets may further include cars, aircraft, boats, incoming missiles or projectiles, or buildings.
Use of conventional API's or other projectiles configured for penetration of armored structures often fail to inflict any damage on thin-skinned targets other than the initial penetration opening resulting from the impact of the projectile with the target. This is often because such projectiles are configured as penetrating structures with much of projectile being dedicated to penetrating rods or other similar structures. As such, these types of projectiles contain a relatively small amount of incendiary or explosive composition therein because the volume needed for larger amounts of such material is consumed by the presence of the penetrating structure. Thus, because such penetrating projectiles contain relatively small amounts of incendiary or explosive materials, the resultant explosions or reactions are, similarly, relatively small.
Moreover, penetrating projectiles conventionally have a relatively strong housing in which the reactive material is disposed. Thus, a relatively substantial impact is required to breach the housing and ignite the reactive material or energetic composition contained therein. The impact of such a projectile with a so-called thin-skinned target is often below the threshold required to breach the housing and cause a reaction of the composition contained therein.
One exemplary projectile that is designed for discrimination between an armored-type target and a thin-skinned target includes that which is described in U.S. Patent Application Publication Number 20030140811. This projectile includes one or more sensors, such as a piezoelectric crystal, that are configured to determine the rate of deceleration of the projectile upon impact with a target. The rate of deceleration will differ depending on whether an armored-type target or a thin-skinned target is being struck. For example, the rate of deceleration of the projectile will be relatively greater (i.e., it will decelerate more quickly) if the projectile strikes an armored target than if it strikes a thin-skinned target. Upon determining the rate of deceleration, a fuse will ignite an incendiary or explosive composition at an optimized time in order to effectively increase the damage to the specific target depending on what type of target is being impacted.
While the projectile disclosed in the US20030140811 publication provides an incendiary or explosive projectile that may provide some effectiveness against thin-skinned targets, the projectile disclosed thereby is a complex structure requiring numerous components and would likely be prohibitively expensive and difficult to fabricate for use in large numbers as is the case with automatic weapons.